z/OS MVS JCL Reference
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CLASS parameter

z/OS MVS JCL Reference

Parameter type

Keyword, optional


Use the CLASS parameter to assign the job to a class. The class you should request depends on the characteristics of the job and your installation’s rules for assigning classes.

Note: The CLASS parameter is ignored for a started task in a JES2 environment. For a started task in a JES3 environment all class related attributes and functions are ignored except device fencing, SPOOL partitioning, and track group allocation. Refer to the z/OS JES3 Initialization and Tuning Guide for more information about class attributes and functions.
In a JES2 system, the assigned job class can affect whether or how a job is executed. A job class can be defined during JES2 initialization as:
  • Held. The system holds any job assigned to this class until the operator releases it.
  • To be copied only. The system copies the input stream for the job directly to a sysout data set and schedules the sysout data set for output processing. The system does not execute the job or allocate devices.
  • To be scanned for job control statement syntax errors. The system does not execute the job or allocate devices.

In a JES2 system, there are a number of factors that determine the order in which a particular job is selected for execution. Therefore, you cannot be assured that job priority (based on the PRTY you assign a job), job class, or the order of job submission will guarantee that the jobs will execute in a particular order. If you need to submit jobs in a specific order, contact your JES2 system programmer for advice based on how your system honors such requests. (z/OS JES2 Initialization and Tuning Guide provides JES2 system programmer procedures concerning job queuing and how to control job execution sequence.)

Considerations for an APPC scheduling environment

The CLASS parameter has no function in an APPC scheduling environment. If you code CLASS, the system will check it for syntax and ignore it.

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